when the car is off my boost gauge is reading 1" vac. i have my mbc set at 20psi. does this mean that i am only running 19psi instead of 20psi?

 

bump

anyone??

 

nobody knows???

 

this is just a guess... but if the car is off there is no reading on the gauge, the needle just drops back kinda like the rest of your gauges.... I just ordered the same gauge so when I install it I'll see how mine reads. How does it read when you have the car on at idle?

 

at idle its about 20-21" hg

 

When your car is off it should read ZERO.

No vacuum or boost at all.

At idle it should be anywhere between 15-20"hg.

If your needle isn't zero'ed when your car is off or even before you put the boost gauge on the car, send it back for a properly calibrated gauge.

In fact, take a picture of your boost gauge when your car is off & post it here.

I had a bad D-Series boost gauge sent to me once, it was off by 5psi

 

so what your sayin is that im running 19psi instead of 20

 

I know some autometers sit a little off, but it doesnt affect the calibration.

 

wait its showing 20psi so i'm only running 19, should i just bump it up to 21 if i want to run 20

 

Hey I installed my DEFI gauge last night, it reads 0 when its off, and about 20 in-hg vac at idle... Under full acceleration it spikes up to like 22 PSI and drops to like 17-18...

 

Defi gauges are VERY accurate. One of the best gauges on the market. IMO

Also people reading the specs of 20hg-15hg remember cams will reduce the amount vaccum you car has so. people with cams could see 15-10hg. If it goes any lower that normally means that your motor is not doing very well.

dan628 - what you are experiencing is very normal. The reason the gauge is reading the boost is falling off is because it is.

Ben

 

Ben,
Ive noticed that with the cams I used to idle around 15hg, recently thats moved up to around 17hg. Would you mind giving a brief explanation of what could cause this?

 

That is very rare for it to do.

Most aftermarket cams have a greater overlap in duration(which gives the cool lug lug at idle)

This causes the vaccum reading to go down.

I have no clue why your went up. What cams did you use? Anything else changed at the time? Cam Gears?

Ben

 

GSC 272/264. Ive only had them for about 3 weeks now or 1k miles. Head studs were also installed at the same time. I had a very pronounced lope after install which has decreased slightly as well.

 

If the gauge doesn't sit at zero when the car is off it's either defective or was damaged in shipping. Do a search on the Honda-Tech forum and you'll find a lot of information about this.